Is it advisable to have a a chipped tooth filled if I have an overbite?

Q. Hi, i am 26 and after previously been told by denitist that i visited when I was 16 to 18 that i dont need braces and now I have been advised i do. I booked an appointment with a new dentist as I chipped a minor part of my bottom front and top front tooth. I firstly thought it was the weakening of the enamel as I like using whitening tooth paste and that can be abrasive. The dentist I visited has put me down for 2 sessions for cleaning and will smooth the chips down though advises me not to get the chips filled as they will come off within a week as I have a slight cross bite with my 3 upper teeth on the left handside and he states that im am subconciously grinding my front teeth at night as i know the alignment is not right. Surely the filling composite is not that weak that it would come off in a week or shall opt for him to file them down slightly as the chips are not that major. I have booked an appointment at your leicester site in the new year to look into my orthodontic options. I am just disappointed that previous dentisits i have gone through have not advised me of the problems i would have faced when i went regulalrly in my teens and therefore feeling complacent I have not been going regulaly as i have not had any painful problems. I am concerned about the getting braces as just with my minor chip on my bottom tooth my tongue was getting caught on the rough edge and got soar and that has caused me to lisp slightly for a week and me working in a call centre that is not great as i have felt really concious though that is healing and now I was advised that i am subconciously grinding my teeth, I feel concious sleeping at night. your input would be greatful,